In February 1924, the production of copper and silver coins of the USSR began. During this period of time, the appearance of USSR coins changed dramatically several times. In 1926, the mint began minting aluminum bronze coins. They repeated the type of coins of previous copper denominations. In 1931, due to the saving of precious metals, the country decided to replace silver coins in denominations of 10, 15 and 20 kopecks with a nickel alloy. In 1935, although the appearance of the coins was changed, they continued to be minted in the same denominations as before. In the new coin design of 1935, the inscription “Workers of all countries unite” disappeared. From 1936 to 1957, there were no changes in the minting of Soviet coins.